My career goal is to better understand the mechanisms of autoimmunity in vitiligo, develop new treatments using animal models, and translate these treatments to human patients. The time and support provided by this award will be critical for me to learn the skills necessary to generate a humanized mouse model of vitiligo, test anti-human cytokine and chemokine blocking antibodies as novel treatments, and gain an understanding of clinical and translational research strategies for future studies. Observations made in my vitiligo clinic prompted me to hypothesize that skin-derived signals recruit T cells to lesional skin. Using a new mouse model of vitiligo developed during my postdoctoral training, I discovered that IFN-3-dependent chemokines were critical for depigmentation and T cell recruitment to the skin. Based on these studies, I hypothesize that IFN-3 and downstream chemokines are required for the development of human vitiligo and that the IFN-3-chemokine axis is an ideal target for new treatments. Animal models do not always reflect human disease mechanisms. A vitiligo model with human tissues is needed to bridge the gap between basic studies in mice and clinical trials in patients. My primary mentor, Dr. Dale Greiner, is the pioneer of a humanized mouse with a functional human immune system. Human skin grafted onto this host will complete a fully human immune-skin axis in which to investigate skin immunity. We hypothesize that this humanized mouse will provide a functional immune-skin axis in which potential new therapies for skin diseases can be tested prior to clinical studies. My research strategy is as follows: Specific Aim 1: Generate and validate a humanized mouse model for skin-immune system functional interactions. Immunodeficient mice will receive autologous human skin and peripheral blood lymphocytes. The functionality of the immune-skin axis will be validated by skin-specific immune challenges. Specific Aim 2: Test neutralizing antibodies against human IFN-3, CXCL9, CXCL10, and CXCR3 as new treatments for vitiligo induced in the humanized mouse system. Vitiligo will be induced in humanized mice. Members of the human IFN-3-chemokine axis will be neutralized with blocking antibodies to determine if they are effective treatments for vitiligo. Future studies will test these antibodies in clinical trials. The training plan in this proposal takes advantage of coursework and a strong mentoring team (Drs. Greiner, Harlan, Turka, Rothstein, and Le Poole) with broad expertise (humanized mouse models, models of autoimmunity, translational/clinical research in autoimmunity, controlling T cell responses in vivo, and basic/translational research in vitiligo) to fill key gaps in my previous training to advance my career goals. This proposal will introduce the first mouse model with a fully immune-skin axis, providing a system to investigate human immune-skin interactions and test new treatments for vitiligo in a human environment. Future studies will focus on translating these findings to clinical studies in order to treat patients with this devastating disease.